Liquid spray dispensers of various types, particularly aerosol and pump dispensers, are well known in the art. Aerosol dispensers use a pre-charged gaseous propellant to pressurize the contents of the package and deliver a product spray when an actuating means is triggered by the user. Aerosol dispensing systems are often preferred over manually actuated pump systems in many cases because these systems deliver a continuous spray of product which requires little energy to dispense, facilitate easy control of the delivery of product, and typically procure finer sprays than from manually activated pump systems due to the higher pressure. Examples of application of aerosols sprayers include spray paints, deodorants, hair sprays, adhesives, disinfectants, and air fresheners.
One problem associated with aerosol packages using a single nozzle for dispensing said product is a limitation of the product use. For example, a nozzle designed for covering large surface areas may not be desirable for covering small surface areas. Such a situation results in wasting large mounts of product, as well as covering objects not intended to be covered with the over spray. The reverse situation is similarly not desired, i.e. the nozzle designed for narrow concentrated sprays will not adequately cover large surface areas, and may overwet the surfaces it does cover, resulting in running of the product.
These problems have been addressed by packaging engineers by tailoring nozzles to provide the widest use for a given aerosol product. Tailoring may involve modifications to the nozzle, particularly the spray pattern or cone angle of the spray, the size of the liquid particles or droplets comprising the spray, and the delivery rate of the spray.
The spray pattern diameter or cone angle is visually observable from the shape of the spray as it exits the nozzle of the package. The spray pattern diameter is determined by several factors, the most important being the key nozzle parameters and the rate of the product flow through the nozzle, For a given product flow rate, a nozzle can be configured, typically by adjusting the exit orifice diameter and length to deliver a specific spray pattern diameter. A more through discussion regarding such parameters is found in A. H. Lefebvre, Atomization and Sprays, Hemisphere Publishing, New York, N.Y.; herein incorporated by reference.
The mean particle size of the spray is likewise discernible and is often characterized on the gross level as either a fine or course spray. Spray particles are formed as the liquid exits the spray nozzle as a conical sheet of liquid, wherein it breaks up in pieces as the liquid sheet interacts with the surrounding air. Engineers can design a nozzle to have a desirable particle size for the flow passing through it by adjusting various dimensions within the nozzle. These adjustments include, but are not limited to, swift chamber diameter, and the length, width, and taper of the tangential ports which feed the swift chamber. By selection of the dimensions, a nozzle can be designed for a specific flow rate to deliver a specific means particle size. Further discussion regarding this subject is found in A. H. Lefebvre, Atomization and Sprays; previously incorporated by reference.
The delivery rate of the spray, hereinafter referred to as spray rate, is harder to visually observe, but, is readily discernible to users of spray products in terms of overwetting or underwetting the object being sprayed with the product. Underwetting or overwetting is a result of lack of control of the product flux which is defined as the mount of the product delivered in grams(g), over a period of time in seconds (see), covering an area in square centimeters (cm2), or (g/see/cm2). The product flux is effected by a number of factors, most importantly the rate of product delivered from the pressurized container. As spray rate is increased, the product flux is increased and can lead to overwetting conditions. Similarly, as spray rate is decreases the product flux is decreased which can lead to underwetting conditions.
In summary the sprays produced by the claimed aerosol package are optimized in terms spray pattern, particle size and spray rate therein providing the user with a package having a variety of optimized uses.